To study the feasibility and safety of One-Shot Dilatation (OSD), versus serial sequential dilatation in tubeless Percutaneous Nephrolithotomy (PCNL). One Hundred and Fifty patients were randomised into two groups; Group A (One-Shot Dilatation), Group B (Serial Dilatation). Twenty-one patients were excluded from the study. Detailed history was taken and full physical examination was performed. Pre-operative routine laboratory investigations were done. Also, non-contrast Computed Tomography of the Urinary Tract (CTUT) and plain urinary tract x-ray were done. Intra-operative assessments of dilatation, total operative, total fluoroscopy and fluoroscopy during dilatation durations were recorded, as well as estimated blood loss. Post-operatively haemoglobin, creatinine levels and CTUT were performed for all patients. Complications, as urinary leakage time, analgesic requirements and hospitalization time were measured. There were statistically significant differences in the intraoperative durations, where Group A had shorter dilatation time, fluoroscopy time during dilatation and total operative time. Group B had a higher complications rate than Group A; 37.9%, 11.3%, respectively. Also, Group B showed haemoglobin drop by 0.44 mg/dl higher than Group A. More doses of analgesia were required for Group B. Hospitalization time and rate of urinary leakage were both in favour of Group A. For patients undergoing Tubeless PCNL, we have concluded that one-shot dilatation seems to be a safer and more feasible technique than Serial dilatation.